Android update activity UI from service

Question

I have a service which is checking for new task all the time  If there is new task  I want to refresh the activity UI to show that info   I did find https   github com commonsguy cw-andtutorials tree master 18-LocalService  this example  Is that a good approch   Any other examples   Thanks

User · Answer

I would recommend checking out Otto  an EventBus tailored specifically to Android  Your Activity UI can listen to events posted on the Bus from the Service  and decouple itself from the backend

User · Answer

See below for my original answer - that pattern has worked well  but recently I ve started using a different approach to Service Activity communication    Use a bound service which enables the Activity to get a direct reference to the Service  thus allowing direct calls on it  rather than using Intents  Use RxJava to execute asynchronous operations  If the Service needs to continue background operations even when no Activity is running  also start the service from the Application class so that it does not get stopped when unbound    The advantages I have found in this approach compared to the startService   LocalBroadcast technique are   No need for data objects to implement Parcelable - this is particularly important to me as I am now sharing code between Android and iOS  using RoboVM  RxJava provides canned  and cross-platform  scheduling  and easy composition of sequential asynchronous operations  This should be more efficient than using a LocalBroadcast  though the overhead of using RxJava may outweigh that    Some example code  First the service   public class AndroidBmService extends Service implements BmService        private static final int PRESSURE RATE   500000       microseconds between pressure updates     private SensorManager sensorManager      private SensorEventListener pressureListener      private ObservableEmitter lt Float gt  pressureObserver      private Observable lt Float gt  pressureObservable       public class LocalBinder extends Binder           public AndroidBmService getService                 return AndroidBmService this                       private IBinder binder   new LocalBinder          Nullable      Override     public IBinder onBind Intent intent            logMsg  Service bound            return binder              Override     public int onStartCommand Intent intent  int flags  int startId            return START NOT STICKY              Override     public void onCreate             super onCreate             sensorManager    SensorManager getSystemService SENSOR SERVICE           Sensor pressureSensor   sensorManager getDefaultSensor Sensor TYPE PRESSURE           if pressureSensor    null              sensorManager registerListener pressureListener   new SensorEventListener                      Override                 public void onSensorChanged SensorEvent event                        if pressureObserver    null                            float lastPressure   event values 0                           float lastPressureAltitude    float   1 - Math pow lastPressure   1013 25  0 190284     145366 45                           pressureObserver onNext lastPressureAltitude                                                             Override                 public void onAccuracyChanged Sensor sensor  int accuracy                                      pressureSensor  PRESSURE RATE               Override     public Observable lt Float gt  observePressure             if pressureObservable    null                pressureObservable   Observable create emitter - gt  pressureObserver   emitter               pressureObservable   pressureObservable share                       return pressureObservable              Override     public void onDestroy             if pressureListener    null              sensorManager unregisterListener pressureListener              And an Activity that binds to the service and receives pressure altitude updates   public class TestActivity extends AppCompatActivity        private ContentTestBinding binding      private ServiceConnection serviceConnection      private AndroidBmService service      private Disposable disposable        Override     protected void onDestroy             if disposable    null              disposable dispose            unbindService serviceConnection           super onDestroy                Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           binding   DataBindingUtil setContentView this  R layout content test           serviceConnection   new ServiceConnection                  Override             public void onServiceConnected ComponentName componentName  IBinder iBinder                    logMsg  BlueMAX service bound                    service     AndroidBmService LocalBinder iBinder  getService                    disposable   service observePressure                        observeOn AndroidSchedulers mainThread                         subscribe altitude - gt                          binding altitude setText                              String format Locale US                                   Pressure Altitude  d feet                                   altitude intValue                                   Override             public void onServiceDisconnected ComponentName componentName                    logMsg  Service disconnected                                     bindService new Intent              this  AndroidBmService class               serviceConnection  BIND AUTO CREATE             The layout for this Activity is    lt  xml version  1 0  encoding  utf-8   gt   lt layout     xmlns android  http   schemas android com apk res android      xmlns app  http   schemas android com apk res-auto      xmlns tools  http   schemas android com tools       gt       lt LinearLayout         android layout width  match parent          android layout height  match parent          tools context  com controlj mfgtest TestActivity  gt            lt TextView             tools text  Pressure              android id    id altitude              android gravity  center horizontal              android layout gravity  center vertical              android layout width  match parent              android layout height  wrap content   gt        lt  LinearLayout gt   lt  layout gt    If the service needs to run in the background without a bound Activity it can be started from the Application class as well in OnCreate   using Context startService       My Original Answer  from 2013    In your service   using COPA as service in example below    Use a LocalBroadCastManager  In your service s onCreate  set up the broadcaster   broadcaster   LocalBroadcastManager getInstance this     When you want to notify the UI of something   static final public String COPA RESULT    com controlj copame backend COPAService REQUEST PROCESSED    static final public String COPA MESSAGE    com controlj copame backend COPAService COPA MSG    public void sendResult String message        Intent intent   new Intent COPA RESULT       if message    null          intent putExtra COPA MESSAGE  message       broadcaster sendBroadcast intent       In your Activity    Create a listener on onCreate   public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       super setContentView R layout copa       receiver   new BroadcastReceiver              Override         public void onReceive Context context  Intent intent                String s   intent getStringExtra COPAService COPA MESSAGE                  do something here                       and register it in onStart    Override protected void onStart         super onStart        LocalBroadcastManager getInstance this  registerReceiver  receiver            new IntentFilter COPAService COPA RESULT             Override protected void onStop         LocalBroadcastManager getInstance this  unregisterReceiver receiver       super onStop

User · Answer

Clyde s solution works  but it is a broadcast  which I am pretty sure will be less efficient than calling a method directly  I could be mistaken  but I think the broadcasts are meant more for inter-application communication   I m assuming you already know how to bind a service with an Activity  I do something sort of like the code below to handle this kind of problem   class MyService extends Service       MyFragment mMyFragment   null      MyFragment mMyOtherFragment   null       private void networkLoop                            received new data for list          if myFragment    null              myFragment updateList                                      received new data for textView         if myFragment   null              myFragment updateText                            received new data for textView         if myOtherFragment   null              myOtherFragment updateSomething                           class MyFragment extends Fragment        public void onResume             super onResume             Assuming your activity bound to your service         getActivity   mMyService mMyFragment this             public void onPause             super onPause             Assuming your activity bound to your service         getActivity   mMyService mMyFragment null             public void updateList             runOnUiThread new Runnable                 public void run                       Update the list                                       public void updateText              as above          class MyOtherFragment extends Fragment                public void onResume             super onResume             Assuming your activity bound to your service         getActivity   mMyService mMyOtherFragment this             public void onPause             super onPause             Assuming your activity bound to your service         getActivity   mMyService mMyOtherFragment null             public void updateSomething      etc          I left out bits for thread safety  which is essential  Make sure to use locks or something like that when checking and using or changing the fragment references on the service

User · Answer

Callback from service to activity to update UI  ResultReceiver receiver   new ResultReceiver new Handler          protected void onReceiveResult int resultCode  Bundle resultData              process results or update UI          Intent instructionServiceIntent   new Intent context  InstructionService class   instructionServiceIntent putExtra  receiver   receiver   context startService instructionServiceIntent

User · Answer

for me the simplest solution was to send a broadcast  in the activity oncreate i registered and defined the broadcast like this  updateUIReciver is defined as a class instance      IntentFilter filter   new IntentFilter      filter addAction  com hello action       updateUIReciver   new BroadcastReceiver                   Override             public void onReceive Context context  Intent intent                      UI update here                            registerReceiver updateUIReciver filter     And from the service you send the intent like this   Intent local   new Intent     local setAction  com hello action     this sendBroadcast local     don t forget to unregister the recover in the activity on destroy    unregisterReceiver updateUIReciver

User · Answer

I would use a bound service to do that and communicate with it by implementing a listener in my activity  So if your app implements myServiceListener  you can register it as a listener in your service after you have bound with it  call listener onUpdateUI from your bound service and update your UI in there

User · Answer

My solution might not be the cleanest but it should work with no problems  The logic is simply to create a static variable to store your data on the Service and update your view each second on your Activity   Let s say that you have a String on your Service that you want to send it to a TextView on your Activity  It should look like this  Your Service    public class TestService extends Service       public static String myString              Do some stuff with myString   Your Activty   public class TestActivity extends Activity       TextView tv       Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           tv   new TextView this           setContentView tv           update            Thread t   new Thread                  Override             public void run                     try                       while   isInterrupted                              Thread sleep 1000                           runOnUiThread new Runnable                                  Override                             public void run                                     update                                                                                                      catch  InterruptedException ignored                                      t start            startService new Intent this  TestService class              private void update                update your interface here         tv setText TestService myString

[android] Android update activity UI from service

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